Is CD27 Ligand the Cause of the Increased Incidence of Epilepsy? A mendelian randomization study

Is CD27 Ligand the Cause of the Increased Incidence of Epilepsy? 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A mendelian randomization study Binbin Zhang, Chen Liang, Shiwen Guo This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4889861/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Epilepsy, a persistent neurological disorder, involves complex pathogenic processes where immunological factors may contribute. The role of CD27 ligand in epilepsy remains unknown. This investigation assesses whether CD27 ligand causally influence generalized and focal epilepsy using Mendelian randomization (MR). Methods We utilized GWAS summary data for CD27 ligand and for both types of epilepsy. Instrumental variables (IVs) were identified following the standard criteria of MR. The primary MR approach employed was the inverse variance weighted (IVW) method, complemented by four additional MR techniques to ensure comprehensive analysis. Extensive sensitivity testing was undertaken to ensure the robustness of the results. Results Findings from the IVW method indicate that an increase by one standard deviation in the level of CD27 ligand elevates the risk of focal epilepsy by 16.6% (OR = 1.166, 95% CI: 1.004–1.354, P = 0.045) and generalized epilepsy by 18.6% (OR = 1.186, 95% CI: 1.063–1.323, P = 0.0023). Parallel results were observed with the four supplementary MR methods. Sensitivity analyses confirmed these findings to be consistent and not influenced by pleiotropy or other biases. Conclusion This MR analysis reveals a causal link between elevated levels of CD27 ligand and an increased risk of epilepsy, highlighting potential therapeutic targets for intervention. Further research is necessary to confirm these findings and to explore the underlying biological mechanisms. Epilepsy CD27 Ligand Mendelian Randomization Focal Epilepsy Generalized Epilepsy Figures Figure 1 Figure 2 Figure 3 1.Introduction Epilepsy is marked by repeated episodes of abrupt and excessive neuronal discharges, leading to temporary brain dysfunction 1 , 2 . Currently, the most accepted classification divides epilepsy into focal and generalized types 3 , 4 . In 2016, estimates suggested that between 39.9 and 54.6 million people worldwide were living with all types of active epilepsy, including idiopathic and secondary forms, with 20.4 to 27.7 million suffering from active idiopathic epilepsy 5 , 6 . The significant adverse effects of epilepsy on individuals' daily lives and work highlight its substantial societal health burden 7 , 8 . Despite ongoing research, the underlying causes of epilepsy remain largely elusive, underscoring the urgent need for further exploration of its pathogenesis, potential new therapeutic targets, and early diagnostic biomarkers. Relevant studies on the immune mechanism in the pathogenesis of epilepsy are frequently reported. For example, in a study of temporal lobe epilepsy patients, increased expression of inflammatory mediators, including 7 chemokines and 10 cytokines, was observed, suggesting the involvement of the immune system in the disease process 9 . Another study found that in a model of temporal lobe epilepsy, infiltration of T lymphocytes and macrophages was detected, which may contribute to epileptogenesis 10 . In an animal model of epilepsy, activation of the IL − 1β system and markers of adaptive immunity were identified during epileptogenesis 11 . Additionally, research has shown that dysfunction of the blood - brain barrier and immune cell infiltration are associated with seizure occurrence and the development of epilepsy 12 . However, the study results of the immune system in epilepsy were inconsistent. This may be related to factors such as the heterogeneity of the disease, the complexity of the immune system, and the limitations of the experimental models. Nevertheless, the immune mechanism remains an important area of research in understanding the pathogenesis of epilepsy. CD27 ligand, also known as CD70, is a transmembrane protein belonging to the tumor necrosis factor (TNF) superfamily. It is expressed on activated immune cells, particularly activated T and B lymphocytes 13 , 14 . The normal physiological function of CD27 ligand involves regulating immune responses through interaction with its receptor CD27. This interaction triggers downstream signaling pathways, such as the NF-κB and MAPK pathways, which play crucial roles in cell proliferation, differentiation, and survival 15 , 16 . Aberrant expression or dysregulation of CD27 ligand has been implicated in neurological diseases such as glioblastoma 17 – 19 , multiple sclerosis 20 , and autoimmune encephalomyelitis 21 . Therefore, this study intends to explore the relationship between CD27 ligand and the pathogenesis of epilepsy using the Mendelian randomization method. Mendelian randomization (MR) utilizes genetically linked variants as instrumental variables (IVs) to establish causal relationships between exposure and outcome. This method leverages the stochastic nature of allele distribution during meiosis to reduce confounding effects and mitigate issues of reverse causality. This research assesses the impact of genetically determined CD27 ligand levels on epilepsy risk, drawing on MR analyses that incorporate GWAS data on CD27 ligand and cases of both focal and generalized epilepsy. 2.Materials and methods 2.1 Study Design This study evaluates the causal impact of CD27 ligand on focal and generalized epilepsy risks. Figure 1 depicts the study's methodological design, and details of the GWAS summary statistics used are provided in Supplementary Table S1 . 2.2 GWAS Summary Data on CD27 Ligand We obtained GWAS summary data on CD27 ligand from a comprehensive study by Mitja I Kurki et al, involving 619 participants who underwent rigorous quality control measures. This data is publicly accessible through Nature ( https://www.nature.com/articles/s41586-022-05473-8 ) 22 . The data for our research comes from publicly available sources. As stated in the original Ethics statement, “Participants in FinnGen provided informed consent for biobank research under the Finnish Biobank Act.” Consequently, no separate approval was required from the institutional review board of the First Affiliated Hospital of Xi'an Jiaotong University for our study. Given the study's retrospective design, the requirement for written informed consent was also waived by the review board. 2.3 GWAS Details on Epilepsy GWAS data for both focal and generalized epilepsy were sourced from the GWAS Catalog database ( https://www.ebi.ac.uk/gwas/home ), detailing 151 cases of focal epilepsy with 456,197 controls, and 290 cases of generalized epilepsy with 456,058 controls. The accession numbers for the focal and generalized epilepsy data are GCST90043754 and GCST90043753, respectively 23 . Our research data were derived from publicly accessible sources. The authors of the data stated in the UKB data section that “All UKB participants provided written informed consent, and the protocols received approval from the National Research Ethics Service Committee.” Thus, the First Affiliated Hospital of Xi'an Jiaotong University institutional review board did not require a separate approval for our study. Due to its retrospective nature, the board also waived the need for written informed consent. 2.4 Selection of IVs Instrumental variables (IVs) for CD27 ligand were chosen for their strong linkage to the exposure and absence of associations with confounders or the outcomes except through the exposure pathways 24 . We set a significance threshold at P < 1e-5 for selecting SNPs, given the scarcity of SNPs meeting a more rigorous genome-wide significance level. SNPs showing linkage disequilibrium (r2 < 0.1 within a 10,000 kb range) or associations with potential confounders were excluded using PhenoScanner V2 ( http://www.phenoscanner.medschl.cam.ac.uk/ ) 25 . Any direct effect on the outcome or palindromic SNPs were also removed. The strength of each IV was confirmed by ensuring F-statistics exceeded 10, minimizing weak instrument bias 26 . 2.5 MR Analysis The primary MR method employed was the Inverse Variance Weighted (IVW) method, which utilizes the ratio of coefficients linking IVs with the exposure and outcome (γWald = β YZ / β XZ ) 27 . These causal effect estimates were aggregated through a random-effects meta-analysis, translating the aggregated β values into odds ratios (OR) using OR = exp( β ) 27 , where the effect measure is the one-standard-deviation increment in CD27 ligand levels. Statistical significance was considered at P < 0.05. Further robustness was added through additional MR methods such as weighted median, simple mode, MR-Egger, and weighted mode. 2.6 Sensitivity Analysis A range of sensitivity analyses was performed to confirm the reliability of our MR results. Cochrane’s Q test evaluated heterogeneity among IV estimates. Both the MR-Egger intercept test and MR-PRESSO global test assessed the presence of horizontal pleiotropy, with non-significance (P > 0.05) indicating negligible pleiotropy. The robustness of findings was further confirmed through leave-one-out analysis to test the influence of each individual IV on overall results. All MR analyses were conducted using R software (version 4.3.3), with causal inference and pleiotropy testing facilitated by the TwoSampleMR and MRPRESSO R packages, respectively. 3.Results 3.1 Instrumental Variable Selection Upon setting a significance cutoff at P < 1e-5 and eliminating SNPs showing linkage disequilibrium, our analysis via PhenoScanner V2 confirmed these SNPs were not associated with known confounders. After further screening to remove SNPs absent in the outcome datasets, those linked to the outcomes at P < 0.05, and palindromic SNPs, we identified 28 SNPs for both focal and generalized epilepsy analyses, detailed in Supplementary Tables S2 and S3. 3.2 MR and Sensitivity Analysis for Focal Epilepsy The Inverse Variance Weighted (IVW) approach indicated a 16.6% elevation in the risk of focal epilepsy per standard deviation increase in CD27 ligand levels, with an odds ratio of 1.166 and a 95% confidence interval of 1.004–1.354 (P = 0.045). Additional MR techniques such as MR-Egger, weighted median, simple mode, and weighted mode, although showing broader confidence intervals, supported these findings (Fig. 2 A). The association plot demonstrated a strong positive causal relationship between increased CD27 ligand levels and the risk of focal epilepsy (Fig. 2 B). Tests for heterogeneity, including Cochrane’s Q, confirmed uniformity across the instrumental variable estimates (Q_pval > 0.05) (Table 1 ). The MR-Egger intercept (intercept = 0.012, P = 0.882) and the MR-PRESSO global test (RSS obs = 21.416, P = 0.748) indicated a lack of significant horizontal pleiotropy (Table 2 ). Leave-one-out analysis supported the consistency of these results, showing no undue influence from any single SNP (Fig. 2 C). Table 1 Heterogeneity Analysis of Focal Epilepsy Using Cochran’s Q Test. Method Cochran’s Q test Q Q_df Q_pval IVW 20.027 25 0.745 MR-Egger 20.005 24 0.697 Table 2 Investigation of Horizontal Pleiotropy in Focal Epilepsy via MR-Egger and MR-PRESSO Tests. MR-Egger intercept test MR-PRESSO global test Intercept SE P -value RSS obs P -value 0.012 0.081 0.882 21.416 0.748 3.3 MR and Sensitivity Analysis: Generalized Epilepsy IVW analysis for generalized epilepsy showed an increased risk of 18.6% per standard deviation increase in CD27 ligand levels, with an odds ratio of 1.186 and a confidence interval of 1.063–1.323 (P = 0.0023). Similarly, additional MR methods agreed with the IVW findings but presented wider confidence intervals for MR-Egger, weighted median, simple mode, and weighted mode (Fig. 3 A). A scatter plot reinforced the significant positive causal relationship (Fig. 3 B). Like the analysis for focal epilepsy, Cochrane’s Q test for generalized epilepsy indicated no significant heterogeneity (Q_pval > 0.05) (Table 3 ). Furthermore, neither the MR-Egger intercept (0.025, P = 0.679) nor the MR-PRESSO global test (RSS obs = 27.407, P = 0.449) showed significant pleiotropy (Table 4 ). Leave-one-out analysis affirmed the robustness of the results, confirming their stability across different instrumental variables (Fig. 3 C). Table 3 Heterogeneity Assessment for Generalized Epilepsy with Cochran’s Q Test. Method Cochran’s Q test Q Q_df Q_pval IVW 25.656 25 0.426 MR-Egger 25.469 24 0.381 Table 4 Pleiotropy Analysis in Generalized Epilepsy Determined by MR-Egger and MR-PRESSO Tests. MR-Egger intercept test MR-PRESSO global test Intercept SE P -value RSS obs P -value 0.025 0.060 0.679 27.407 0.449 Overall, MR analyses for both focal and generalized epilepsy consistently revealed that higher levels of CD27 ligand are causally linked to an increased risk of epilepsy, emphasizing the potential of targeting this protein in preventive and therapeutic strategies. 4.Discussion In this research, we establish a causal link between heightened levels of CD27 ligand and an increased likelihood of epilepsy, employing a comprehensive two-sample MR approach. Both the MR studies targeting focal and generalized epilepsy indicated a significant causal effect. We conducted numerous sensitivity analysis to validate the dependability of our MR outcomes. These results are crucial for deepening our comprehension of the mechanisms underlying epilepsy and may guide future prophylactic and therapeutic strategies targeting CD27 ligand. Review of the literature reveals that the immune mechanism is increasingly recognized as an important aspect in epilepsy. For example, in 15 cases of Temporal lobe epilepsy, it was found that neurons were killed by T cells 28 . In a prospective study of 23 patients with Autoimmune epilepsy and 11 healthy controls, it was discovered that the levels of B cells and follicular helper T-cell subsets in the blood of the cases were significantly increased 29 . In the serum and cerebrospinal fluid of a dog model of idiopathic epilepsy, a significant elevation in the level of Th17 cells was also observed 30 . However, another case study revealed that in cases of temporal lobe epilepsy, T cell was associated with hippocampal neuronal loss, rather than epileptic seizures 31 .Through targeted transcriptomics of the postoperative brain tissue in 53 pediatric epilepsy surgery cases, the presence of T cells with both innate and adaptive immune responses was identified 32 . Furthermore, in a mouse model of inflammation in hippocampal neurons induced by the autoantigen ovalbumin, it was found that CD8 + T lymphocytes promote the transformation of Limbic encephalitis to temporal lobe epilepsy with hippocampal sclerosis 33 . Moreover, in the surgically resected brain tissues of 29 patients with drug-resistant pediatric epilepsy, a significant increase in memory CD4 + and CD8 + T cells was detected 34 . In a prospective study of 20 cases of temporal lobe epilepsy and 19 controls, it was found that in the peripheral blood of the case group, there was a higher expression of HLA-DR, CD69, CTLA-4, CD25, IL-23R, IFN-γ, TNF, and IL-17 in CD4(+) lymphocytes compared to the controls, and the expression of Granzyme A, CTLA-4, IL-23R, and IL-17 was also elevated in CD8(+) T cells in the case group compared to the control group 35 . Specifically, in the context of CD27 ligand, several studies have highlighted their potential role in central nervous system diseases. For example, it has been found that CD27 ligand expression is elevated in recurrent glioblastoma and CD27 ligand knockdown reduces tumorigenicity in vitro and in vivo 36 . In addition, the high expression of CD70 in glioblastoma is involved in promoting tumor migration and macrophage infiltration in glioblastoma 37 . However, some studies have found that soluble CD27 ligand promotes the proliferation of glioblastoma, but it actually prolongs the survival time of syngeneic VM/Dk mice bearing intracranial SMA − 560 gliomas 38 . On the contrary, glioblastoma can also lead to the apoptosis of T lymphocytes through the downstream signaling pathway of CD27 ligand 39 . Furthermore, in multiple sclerosis, it has been found that CD27 ligand is significantly highly expressed in T lymphocytes 40 . Additionally, B lymphocytes expressing CD27 ligand can exacerbate the progression of autoimmune encephalomyelitis in MOG - specific TCR transgenic mice 21 , 41 . Our MR analysis uniquely demonstrates that elevated levels of CD27 ligand are linked to a higher incidence of epilepsy. This analysis utilizes genetic variants as instrumental variables (IVs), which are determined during meiosis and are unaffected by environmental factors, adhering to the principles of random allocation 42 . Consequently, MR studies are often viewed as natural randomized controlled trials (RCTs). Given the ethical challenges associated with conducting traditional RCTs on critical health indicators, MR provides a valuable alternative 43 . Our findings validate the hypothesis that CD27 ligand leads to an increased incidence of epilepsy. This study presents several significant strengths. Firstly, it is based on extensive GWAS summary statistics, providing robust statistical power. Secondly, the application of multiple MR methodologies and sensitivity analyses enhances the validity of our results. Additionally, the separate analysis of focal and generalized epilepsy data bolsters the robustness of our conclusions. However, the study also has notable limitations that should be considered. Primarily, the GWAS summary statistics are derived from predominantly European populations, limiting the generalizability of our findings to other ethnic and racial groups. There is a clear need for further studies involving more diverse populations to confirm these results. Moreover, only a limited number of CD27 ligand-related SNPs met the stringent genome-wide significance criteria, necessitating the use of a less stringent threshold (P < 1e-5). Furthermore, the small sample sizes for specific exposures pose additional challenges to the study's conclusions. Future studies should aim to replicate these MR analyses using larger and more varied GWAS data from individuals without neurological disorders to more comprehensively evaluate the role of CD27 ligand in epilepsy. Lastly, the biological mechanisms by which CD27 ligand levels influence epilepsy risk remain to be elucidated and require further investigation. Conclusion The present MR study supports a causal relationship between elevated genetically determined CD27 ligand levels and increased epilepsy risk. Abbreviations MR: Mendelian Randomization; GWAS: Genome-Wide Association Study; IVs: Instrumental Variables; SNP: Single Nucleotide Polymorphisms; IVW: Inverse Variance Weighted Method; CI: confidence interval. Declarations Ethical Approval and consent to participate The sourcing of summary data on CD27 ligand and epilepsy from GWAS studies was accomplished by referencing previously published research, with ethical approvals being managed by the original conducting bodies. Our research did not require the collection of new fundamental data, and all analyses were conducted online, eliminating the necessity for additional ethical approval in our particular circumstance. Consent for publication Not applicable. Competing interests The authors declare that they have no competing interests. Funding The project was financed by the Key Research and Development Plan of Shaanxi Province, China [grant number 2024SF-YBXM-047]. Data Availability The GWAS data used in this study can be accessed through open-access resources: Mitja I Kurki 's research (https://www.nature.com/articles/s41586-022-05473-8) and the GWAS Catalog database (https://www.ebi.ac.uk/gwas/home). The registration numbers for focal and generalized epilepsy data are GCST90043754 and GCST90043753 respectively. Author contributions Conceptualization, SW.G.; methodology, BB.Z.; software, BB.Z.; prepare Figs. 1–3, BB.Z.; validation, C.L.; investigation, BB.Z.; resources, BB.Z.; writing—original draft preparation, BB.Z..; writing—review and editing, SW.G. and C.L.; supervision, SW.G. and C.L.; project administration, C.L.; funding acquisition, C.L. All authors have read and agreed to the published version of the manuscript. Acknowledgements Gratitude is extended to all the organizations that have provided access to their GWAS summary-level data. Supplementary Information Supplementary data can be found in the supplementary_tables.xlsx. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4889861","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":339345908,"identity":"befdd6de-c2b1-4c88-9b8e-a040a670eee7","order_by":0,"name":"Binbin Zhang","email":"","orcid":"","institution":"The First Affiliated Hospital of Xi'an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Binbin","middleName":"","lastName":"Zhang","suffix":""},{"id":339345909,"identity":"597915a8-6bbf-4957-a9a3-a29cf75b57cd","order_by":1,"name":"Chen Liang","email":"","orcid":"","institution":"The First Affiliated Hospital of Xi'an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Chen","middleName":"","lastName":"Liang","suffix":""},{"id":339345910,"identity":"e0d1892c-7b5c-4c78-b8f1-529343d00b32","order_by":2,"name":"Shiwen Guo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6ElEQVRIiWNgGAWjYBACNvb2Awc+VPyTs5//+OCDhIoawlr4eM4kPpxx5oCxAUNassGDM8cIa5GTSDA25m07kLiBIcdM8mELMxEO4zmQJsHbdidxO8MZs4rEBjYG/vbuBAJ+aTwmIXHumfHOxrayG4k7ZBgkzpzdQNgWgzJm2YbDzNtuJJ5hYzCQyCWgRSLBTCKBjZmx4RiDWUFiGzNRWowNDrQdVtxwhsWMgTgtoEBuOJNmLDmDLVki4cwxHoJ+kW9vP3D4T4WNHL8E88GPPypq5Pjbe/FrwQA8pCkfBaNgFIyCUYAVAAAYpVCQ84C21wAAAABJRU5ErkJggg==","orcid":"","institution":"The First Affiliated Hospital of Xi'an Jiaotong University","correspondingAuthor":true,"prefix":"","firstName":"Shiwen","middleName":"","lastName":"Guo","suffix":""}],"badges":[],"createdAt":"2024-08-10 04:06:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4889861/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4889861/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":64103280,"identity":"4e43da85-0a14-49bc-b07c-2685cf12dd85","added_by":"auto","created_at":"2024-09-06 22:56:19","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":71483,"visible":true,"origin":"","legend":"\u003cp\u003eDiagrammatic Representation of the Mendelian Randomization Study Process.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4889861/v1/781cbc00de9187e441224e4b.jpg"},{"id":64103304,"identity":"d8e00488-10ef-4e68-81c3-3efc6e714b92","added_by":"auto","created_at":"2024-09-06 23:04:19","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":396137,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAnalysis of the Effect of CD27 Ligand on the Risk of Focal Epilepsy Using Multiple Mendelian Randomization Approaches.\u003c/strong\u003e (A) Summary of Mendelian Randomization Estimates in Forest Plots. (B) Causal Relationship Depicted in Scatter Plots.(C) Stability of Results Explored through Leave-One-Out Sensitivity Analysis.\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4889861/v1/130cd1b9beec2d8c3ee267d6.jpg"},{"id":64103282,"identity":"aa9014a5-06a9-422b-bc23-a390885f97de","added_by":"auto","created_at":"2024-09-06 22:56:19","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":394699,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eExamination of the Influence of CD27 Ligand on Generalized Epilepsy Using Diverse MR Methods. \u003c/strong\u003e(A) Compilation of Mendelian Randomization Results in Forest Plots.(B) Visualization of Causal Inference in Scatter Plots.(C) Consistency Assessment of Findings via Leave-One-Out Sensitivity Analysis.\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4889861/v1/e10ae5c8f560d05379035568.jpg"},{"id":99316663,"identity":"abd96a5e-ed54-4154-bd0c-4564db7af1fd","added_by":"auto","created_at":"2025-12-31 16:28:54","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1623548,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4889861/v1/1445afa0-9a38-4dfb-a6ca-6bce28b90fc1.pdf"},{"id":64103281,"identity":"c795629b-1867-466a-82d3-dc0f99786679","added_by":"auto","created_at":"2024-09-06 22:56:19","extension":"xlsx","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":19913,"visible":true,"origin":"","legend":"","description":"","filename":"supplementarytables.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-4889861/v1/7c4190609475d6b7b11b6513.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Is CD27 Ligand the Cause of the Increased Incidence of Epilepsy? A mendelian randomization study","fulltext":[{"header":"1.Introduction","content":"\u003cp\u003eEpilepsy is marked by repeated episodes of abrupt and excessive neuronal discharges, leading to temporary brain dysfunction\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. Currently, the most accepted classification divides epilepsy into focal and generalized types\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. In 2016, estimates suggested that between 39.9 and 54.6\u0026nbsp;million people worldwide were living with all types of active epilepsy, including idiopathic and secondary forms, with 20.4 to 27.7\u0026nbsp;million suffering from active idiopathic epilepsy\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. The significant adverse effects of epilepsy on individuals' daily lives and work highlight its substantial societal health burden\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Despite ongoing research, the underlying causes of epilepsy remain largely elusive, underscoring the urgent need for further exploration of its pathogenesis, potential new therapeutic targets, and early diagnostic biomarkers.\u003c/p\u003e \u003cp\u003eRelevant studies on the immune mechanism in the pathogenesis of epilepsy are frequently reported. For example, in a study of temporal lobe epilepsy patients, increased expression of inflammatory mediators, including 7 chemokines and 10 cytokines, was observed, suggesting the involvement of the immune system in the disease process\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Another study found that in a model of temporal lobe epilepsy, infiltration of T lymphocytes and macrophages was detected, which may contribute to epileptogenesis\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. In an animal model of epilepsy, activation of the IL \u0026minus;\u0026thinsp;1β system and markers of adaptive immunity were identified during epileptogenesis\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. Additionally, research has shown that dysfunction of the blood - brain barrier and immune cell infiltration are associated with seizure occurrence and the development of epilepsy\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. However, the study results of the immune system in epilepsy were inconsistent. This may be related to factors such as the heterogeneity of the disease, the complexity of the immune system, and the limitations of the experimental models. Nevertheless, the immune mechanism remains an important area of research in understanding the pathogenesis of epilepsy.\u003c/p\u003e \u003cp\u003eCD27 ligand, also known as CD70, is a transmembrane protein belonging to the tumor necrosis factor (TNF) superfamily. It is expressed on activated immune cells, particularly activated T and B lymphocytes\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. The normal physiological function of CD27 ligand involves regulating immune responses through interaction with its receptor CD27. This interaction triggers downstream signaling pathways, such as the NF-κB and MAPK pathways, which play crucial roles in cell proliferation, differentiation, and survival\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. Aberrant expression or dysregulation of CD27 ligand has been implicated in neurological diseases such as glioblastoma\u003csup\u003e\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e, multiple sclerosis\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e, and autoimmune encephalomyelitis\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. Therefore, this study intends to explore the relationship between CD27 ligand and the pathogenesis of epilepsy using the Mendelian randomization method.\u003c/p\u003e \u003cp\u003eMendelian randomization (MR) utilizes genetically linked variants as instrumental variables (IVs) to establish causal relationships between exposure and outcome. This method leverages the stochastic nature of allele distribution during meiosis to reduce confounding effects and mitigate issues of reverse causality. This research assesses the impact of genetically determined CD27 ligand levels on epilepsy risk, drawing on MR analyses that incorporate GWAS data on CD27 ligand and cases of both focal and generalized epilepsy.\u003c/p\u003e"},{"header":"2.Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Study Design\u003c/h2\u003e \u003cp\u003eThis study evaluates the causal impact of CD27 ligand on focal and generalized epilepsy risks. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e depicts the study's methodological design, and details of the GWAS summary statistics used are provided in Supplementary Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 GWAS Summary Data on CD27 Ligand\u003c/h2\u003e \u003cp\u003eWe obtained GWAS summary data on CD27 ligand from a comprehensive study by Mitja I Kurki et al, involving 619 participants who underwent rigorous quality control measures. This data is publicly accessible through Nature (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.nature.com/articles/s41586-022-05473-8\u003c/span\u003e\u003cspan address=\"https://www.nature.com/articles/s41586-022-05473-8\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e)\u003csup\u003e22\u003c/sup\u003e. The data for our research comes from publicly available sources. As stated in the original Ethics statement, \u0026ldquo;Participants in FinnGen provided informed consent for biobank research under the Finnish Biobank Act.\u0026rdquo; Consequently, no separate approval was required from the institutional review board of the First Affiliated Hospital of Xi'an Jiaotong University for our study. Given the study's retrospective design, the requirement for written informed consent was also waived by the review board.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 GWAS Details on Epilepsy\u003c/h2\u003e \u003cp\u003eGWAS data for both focal and generalized epilepsy were sourced from the GWAS Catalog database (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.ebi.ac.uk/gwas/home\u003c/span\u003e\u003cspan address=\"https://www.ebi.ac.uk/gwas/home\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e), detailing 151 cases of focal epilepsy with 456,197 controls, and 290 cases of generalized epilepsy with 456,058 controls. The accession numbers for the focal and generalized epilepsy data are GCST90043754 and GCST90043753, respectively\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Our research data were derived from publicly accessible sources. The authors of the data stated in the UKB data section that \u0026ldquo;All UKB participants provided written informed consent, and the protocols received approval from the National Research Ethics Service Committee.\u0026rdquo; Thus, the First Affiliated Hospital of Xi'an Jiaotong University institutional review board did not require a separate approval for our study. Due to its retrospective nature, the board also waived the need for written informed consent.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Selection of IVs\u003c/h2\u003e \u003cp\u003eInstrumental variables (IVs) for CD27 ligand were chosen for their strong linkage to the exposure and absence of associations with confounders or the outcomes except through the exposure pathways\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e. We set a significance threshold at P\u0026thinsp;\u0026lt;\u0026thinsp;1e-5 for selecting SNPs, given the scarcity of SNPs meeting a more rigorous genome-wide significance level. SNPs showing linkage disequilibrium (r2\u0026thinsp;\u0026lt;\u0026thinsp;0.1 within a 10,000 kb range) or associations with potential confounders were excluded using PhenoScanner V2 (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.phenoscanner.medschl.cam.ac.uk/\u003c/span\u003e\u003cspan address=\"http://www.phenoscanner.medschl.cam.ac.uk/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e)\u003csup\u003e25\u003c/sup\u003e. Any direct effect on the outcome or palindromic SNPs were also removed. The strength of each IV was confirmed by ensuring F-statistics exceeded 10, minimizing weak instrument bias\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 MR Analysis\u003c/h2\u003e \u003cp\u003eThe primary MR method employed was the Inverse Variance Weighted (IVW) method, which utilizes the ratio of coefficients linking IVs with the exposure and outcome (γWald\u0026thinsp;=\u0026thinsp;\u003cem\u003eβ\u003c/em\u003e\u003csub\u003eYZ\u003c/sub\u003e/\u003cem\u003eβ\u003c/em\u003e\u003csub\u003eXZ\u003c/sub\u003e)\u003csup\u003e27\u003c/sup\u003e. These causal effect estimates were aggregated through a random-effects meta-analysis, translating the aggregated \u003cem\u003eβ\u003c/em\u003e values into odds ratios (OR) using OR\u0026thinsp;=\u0026thinsp;exp(\u003cem\u003eβ\u003c/em\u003e)\u003csup\u003e27\u003c/sup\u003e, where the effect measure is the one-standard-deviation increment in CD27 ligand levels. Statistical significance was considered at P\u0026thinsp;\u0026lt;\u0026thinsp;0.05. Further robustness was added through additional MR methods such as weighted median, simple mode, MR-Egger, and weighted mode.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Sensitivity Analysis\u003c/h2\u003e \u003cp\u003eA range of sensitivity analyses was performed to confirm the reliability of our MR results. Cochrane\u0026rsquo;s Q test evaluated heterogeneity among IV estimates. Both the MR-Egger intercept test and MR-PRESSO global test assessed the presence of horizontal pleiotropy, with non-significance (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05) indicating negligible pleiotropy. The robustness of findings was further confirmed through leave-one-out analysis to test the influence of each individual IV on overall results.\u003c/p\u003e \u003cp\u003eAll MR analyses were conducted using R software (version 4.3.3), with causal inference and pleiotropy testing facilitated by the TwoSampleMR and MRPRESSO R packages, respectively.\u003c/p\u003e \u003c/div\u003e"},{"header":"3.Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Instrumental Variable Selection\u003c/h2\u003e \u003cp\u003eUpon setting a significance cutoff at P\u0026thinsp;\u0026lt;\u0026thinsp;1e-5 and eliminating SNPs showing linkage disequilibrium, our analysis via PhenoScanner V2 confirmed these SNPs were not associated with known confounders. After further screening to remove SNPs absent in the outcome datasets, those linked to the outcomes at P\u0026thinsp;\u0026lt;\u0026thinsp;0.05, and palindromic SNPs, we identified 28 SNPs for both focal and generalized epilepsy analyses, detailed in Supplementary Tables S2 and S3.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2 MR and Sensitivity Analysis for Focal Epilepsy\u003c/h2\u003e \u003cp\u003eThe Inverse Variance Weighted (IVW) approach indicated a 16.6% elevation in the risk of focal epilepsy per standard deviation increase in CD27 ligand levels, with an odds ratio of 1.166 and a 95% confidence interval of 1.004\u0026ndash;1.354 (P\u0026thinsp;=\u0026thinsp;0.045). Additional MR techniques such as MR-Egger, weighted median, simple mode, and weighted mode, although showing broader confidence intervals, supported these findings (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA). The association plot demonstrated a strong positive causal relationship between increased CD27 ligand levels and the risk of focal epilepsy (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTests for heterogeneity, including Cochrane\u0026rsquo;s Q, confirmed uniformity across the instrumental variable estimates (Q_pval\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The MR-Egger intercept (intercept\u0026thinsp;=\u0026thinsp;0.012, P\u0026thinsp;=\u0026thinsp;0.882) and the MR-PRESSO global test (RSS obs\u0026thinsp;=\u0026thinsp;21.416, P\u0026thinsp;=\u0026thinsp;0.748) indicated a lack of significant horizontal pleiotropy (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Leave-one-out analysis supported the consistency of these results, showing no undue influence from any single SNP (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eHeterogeneity Analysis of Focal Epilepsy Using Cochran\u0026rsquo;s Q Test.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMethod\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eCochran\u0026rsquo;s Q test\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQ\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eQ_df\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eQ_pval\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIVW\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e20.027\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.745\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMR-Egger\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e20.005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.697\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eInvestigation of Horizontal Pleiotropy in Focal Epilepsy via MR-Egger and MR-PRESSO Tests.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003eMR-Egger intercept test\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003eMR-PRESSO global test\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntercept\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRSS obs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.012\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.081\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.882\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e21.416\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.748\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.3 MR and Sensitivity Analysis: Generalized Epilepsy\u003c/h2\u003e \u003cp\u003eIVW analysis for generalized epilepsy showed an increased risk of 18.6% per standard deviation increase in CD27 ligand levels, with an odds ratio of 1.186 and a confidence interval of 1.063\u0026ndash;1.323 (P\u0026thinsp;=\u0026thinsp;0.0023). Similarly, additional MR methods agreed with the IVW findings but presented wider confidence intervals for MR-Egger, weighted median, simple mode, and weighted mode (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). A scatter plot reinforced the significant positive causal relationship (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eLike the analysis for focal epilepsy, Cochrane\u0026rsquo;s Q test for generalized epilepsy indicated no significant heterogeneity (Q_pval\u0026thinsp;\u0026gt;\u0026thinsp;0.05) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Furthermore, neither the MR-Egger intercept (0.025, P\u0026thinsp;=\u0026thinsp;0.679) nor the MR-PRESSO global test (RSS obs\u0026thinsp;=\u0026thinsp;27.407, P\u0026thinsp;=\u0026thinsp;0.449) showed significant pleiotropy (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Leave-one-out analysis affirmed the robustness of the results, confirming their stability across different instrumental variables (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eC).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eHeterogeneity Assessment for Generalized Epilepsy with Cochran\u0026rsquo;s Q Test.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMethod\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eCochran\u0026rsquo;s Q test\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQ\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eQ_df\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eQ_pval\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIVW\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25.656\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.426\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMR-Egger\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e25.469\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.381\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePleiotropy Analysis in Generalized Epilepsy Determined by MR-Egger and MR-PRESSO Tests.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003eMR-Egger intercept test\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003eMR-PRESSO global test\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntercept\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRSS obs\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.060\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.679\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e27.407\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.449\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eOverall, MR analyses for both focal and generalized epilepsy consistently revealed that higher levels of CD27 ligand are causally linked to an increased risk of epilepsy, emphasizing the potential of targeting this protein in preventive and therapeutic strategies.\u003c/p\u003e \u003c/div\u003e"},{"header":"4.Discussion","content":"\u003cp\u003eIn this research, we establish a causal link between heightened levels of CD27 ligand and an increased likelihood of epilepsy, employing a comprehensive two-sample MR approach. Both the MR studies targeting focal and generalized epilepsy indicated a significant causal effect. We conducted numerous sensitivity analysis to validate the dependability of our MR outcomes. These results are crucial for deepening our comprehension of the mechanisms underlying epilepsy and may guide future prophylactic and therapeutic strategies targeting CD27 ligand.\u003c/p\u003e \u003cp\u003eReview of the literature reveals that the immune mechanism is increasingly recognized as an important aspect in epilepsy. For example, in 15 cases of Temporal lobe epilepsy, it was found that neurons were killed by T cells\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. In a prospective study of 23 patients with Autoimmune epilepsy and 11 healthy controls, it was discovered that the levels of B cells and follicular helper T-cell subsets in the blood of the cases were significantly increased\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. In the serum and cerebrospinal fluid of a dog model of idiopathic epilepsy, a significant elevation in the level of Th17 cells was also observed\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. However, another case study revealed that in cases of temporal lobe epilepsy, T cell was associated with hippocampal neuronal loss, rather than epileptic seizures\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e.Through targeted transcriptomics of the postoperative brain tissue in 53 pediatric epilepsy surgery cases, the presence of T cells with both innate and adaptive immune responses was identified\u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. Furthermore, in a mouse model of inflammation in hippocampal neurons induced by the autoantigen ovalbumin, it was found that CD8\u0026thinsp;+\u0026thinsp;T lymphocytes promote the transformation of Limbic encephalitis to temporal lobe epilepsy with hippocampal sclerosis\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. Moreover, in the surgically resected brain tissues of 29 patients with drug-resistant pediatric epilepsy, a significant increase in memory CD4\u0026thinsp;+\u0026thinsp;and CD8\u0026thinsp;+\u0026thinsp;T cells was detected\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e. In a prospective study of 20 cases of temporal lobe epilepsy and 19 controls, it was found that in the peripheral blood of the case group, there was a higher expression of HLA-DR, CD69, CTLA-4, CD25, IL-23R, IFN-γ, TNF, and IL-17 in CD4(+) lymphocytes compared to the controls, and the expression of Granzyme A, CTLA-4, IL-23R, and IL-17 was also elevated in CD8(+) T cells in the case group compared to the control group\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eSpecifically, in the context of CD27 ligand, several studies have highlighted their potential role in central nervous system diseases. For example, it has been found that CD27 ligand expression is elevated in recurrent glioblastoma and CD27 ligand knockdown reduces tumorigenicity in vitro and in vivo\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. In addition, the high expression of CD70 in glioblastoma is involved in promoting tumor migration and macrophage infiltration in glioblastoma\u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. However, some studies have found that soluble CD27 ligand promotes the proliferation of glioblastoma, but it actually prolongs the survival time of syngeneic VM/Dk mice bearing intracranial SMA \u0026minus;\u0026thinsp;560 gliomas\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e. On the contrary, glioblastoma can also lead to the apoptosis of T lymphocytes through the downstream signaling pathway of CD27 ligand\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. Furthermore, in multiple sclerosis, it has been found that CD27 ligand is significantly highly expressed in T lymphocytes\u003csup\u003e\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e. Additionally, B lymphocytes expressing CD27 ligand can exacerbate the progression of autoimmune encephalomyelitis in MOG - specific TCR transgenic mice\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eOur MR analysis uniquely demonstrates that elevated levels of CD27 ligand are linked to a higher incidence of epilepsy. This analysis utilizes genetic variants as instrumental variables (IVs), which are determined during meiosis and are unaffected by environmental factors, adhering to the principles of random allocation\u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e. Consequently, MR studies are often viewed as natural randomized controlled trials (RCTs). Given the ethical challenges associated with conducting traditional RCTs on critical health indicators, MR provides a valuable alternative\u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e. Our findings validate the hypothesis that CD27 ligand leads to an increased incidence of epilepsy.\u003c/p\u003e \u003cp\u003eThis study presents several significant strengths. Firstly, it is based on extensive GWAS summary statistics, providing robust statistical power. Secondly, the application of multiple MR methodologies and sensitivity analyses enhances the validity of our results. Additionally, the separate analysis of focal and generalized epilepsy data bolsters the robustness of our conclusions.\u003c/p\u003e \u003cp\u003eHowever, the study also has notable limitations that should be considered. Primarily, the GWAS summary statistics are derived from predominantly European populations, limiting the generalizability of our findings to other ethnic and racial groups. There is a clear need for further studies involving more diverse populations to confirm these results. Moreover, only a limited number of CD27 ligand-related SNPs met the stringent genome-wide significance criteria, necessitating the use of a less stringent threshold (P\u0026thinsp;\u0026lt;\u0026thinsp;1e-5). Furthermore, the small sample sizes for specific exposures pose additional challenges to the study's conclusions. Future studies should aim to replicate these MR analyses using larger and more varied GWAS data from individuals without neurological disorders to more comprehensively evaluate the role of CD27 ligand in epilepsy. Lastly, the biological mechanisms by which CD27 ligand levels influence epilepsy risk remain to be elucidated and require further investigation.\u003c/p\u003e "},{"header":"Conclusion","content":"\u003cp\u003eThe present MR study supports a causal relationship between elevated genetically determined CD27 ligand levels and increased epilepsy risk.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eMR: Mendelian Randomization; GWAS: Genome-Wide Association Study; IVs: Instrumental Variables; SNP: Single Nucleotide Polymorphisms; IVW: Inverse Variance Weighted Method;\u0026nbsp;CI: confidence interval.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical Approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe sourcing of summary data on CD27 ligand and epilepsy from GWAS studies was accomplished by referencing previously published research, with ethical approvals being managed by the original conducting bodies. Our research did not require the collection of new fundamental data, and all analyses were conducted online, eliminating the necessity for additional ethical approval in our particular circumstance.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe project was financed by the Key Research and Development Plan of Shaanxi Province, China [grant number 2024SF-YBXM-047].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe GWAS data used in this study can be accessed through open-access resources: Mitja I Kurki \u0026apos;s research (https://www.nature.com/articles/s41586-022-05473-8) and the GWAS Catalog database (https://www.ebi.ac.uk/gwas/home). The registration numbers for focal and generalized epilepsy data are GCST90043754 and GCST90043753 respectively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization, SW.G.; methodology, BB.Z.; software, BB.Z.; prepare Figs. 1\u0026ndash;3, BB.Z.; validation, C.L.; investigation, BB.Z.; resources, BB.Z.; writing\u0026mdash;original draft preparation, BB.Z..; writing\u0026mdash;review and editing, SW.G. and C.L.; supervision, SW.G. and C.L.; project administration, C.L.; funding acquisition, C.L. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGratitude is extended to all the organizations that have provided access to their GWAS summary-level data.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSupplementary Information\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSupplementary data can be found in the supplementary_tables.xlsx.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eFisher RS, Acevedo C, Arzimanoglou A, et al. ILAE Official Report: A practical clinical definition of epilepsy. Epilepsia. 2014;55:475\u0026ndash;82.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi J, Singh G, Keezer MR, Sander JW. Thinking of epilepsy as a symptom. Lancet Neurol. 2024;23:770\u0026ndash;1.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZuberi SM, Brunklaus A. 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J Neuroimmunol. 2013;255:8\u0026ndash;17.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKurki MI, Karjalainen J, Palta P, et al. FinnGen provides genetic insights from a well-phenotyped isolated population. Nature. 2023;613:508\u0026ndash;.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJiang LD, Zheng ZL, Fang HL, Yang J. A generalized linear mixed model association tool for biobank-scale data. Nat Genet. 2021;53:1616\u0026ndash;.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePower GM, Sanderson E, Pagoni P, et al. Methodological approaches, challenges, and opportunities in the application of Mendelian randomisation to lifecourse epidemiology: A systematic literature review. Eur J Epidemiol. 2024;39:501\u0026ndash;20.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKamat MA, Blackshaw JA, Young R, et al. PhenoScanner V2: an expanded tool for searching human genotype-phenotype associations. Bioinformatics. 2019;35:4851\u0026ndash;3.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBowden J, Del Greco MF, Minelli C, Smith GD, Sheehan NA, Thompson JR. Assessing the suitability of summary data for two-sample Mendelian randomization analyses using MR-Egger regression: the role of the statistic. Int J Epidemiol. 2016;45:1961\u0026ndash;74.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoehm FJ, Zhou X. Statistical methods for Mendelian randomization in genome-wide association studies: A review. Comput Struct Biotec. 2022;20:2338\u0026ndash;51.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTr\u0026ouml;scher AR, Mair KM, Verd\u0026uacute; de Juan L, et al. Temporal lobe epilepsy with GAD antibodies: neurons killed by T cells not by complement membrane attack complex. Brain. 2023;146:1436\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHara A, Chihara N, Akatani R et al. Circulating plasmablasts and follicular helper T-cell subsets are associated with antibody-positive autoimmune epilepsy. Front Immunol 2022;13.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKnebel A, K\u0026auml;mpe A, Carlson R, Rohn K, Tipold A. Th17 cell-mediated immune response in a subpopulation of dogs with idiopathic epilepsy. PLoS ONE 2022;17.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTr\u0026ouml;scher AR, Sakaraki E, Mair KM, et al. T cell numbers correlate with neuronal loss rather than with seizure activity in medial temporal lobe epilepsy. Epilepsia. 2021;62:1343\u0026ndash;53.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChang JW, Reyes SD, Faure-Kumar E et al. Clonally Focused Public and Private T Cells in Resected Brain Tissue From Surgeries to Treat Children With Intractable Seizures. Front Immunol 2021;12.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePitsch J, van Loo KMJ, Gallus M, et al. 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Cell Mol Immunol. 2019;16:652\u0026ndash;65.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNakajima A, Oshima H, Nohara C, et al. Involvement of CD70-CD27 interactions in the induction of experimental autoimmune encephalomyelitis. J Neuroimmunol. 2000;109:188\u0026ndash;96.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePaternoster L, Tilling K, Smith GD. Genetic epidemiology and Mendelian randomization for informing disease therapeutics: Conceptual and methodological challenges. Plos Genet 2017;13.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHingorani A, Humphries S. Nature's randomised trials. Lancet. 2005;366:1906\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Epilepsy, CD27 Ligand, Mendelian Randomization, Focal Epilepsy, Generalized Epilepsy","lastPublishedDoi":"10.21203/rs.3.rs-4889861/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4889861/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eEpilepsy, a persistent neurological disorder, involves complex pathogenic processes where immunological factors may contribute. The role of CD27 ligand in epilepsy remains unknown. This investigation assesses whether CD27 ligand causally influence generalized and focal epilepsy using Mendelian randomization (MR).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eWe utilized GWAS summary data for CD27 ligand and for both types of epilepsy. Instrumental variables (IVs) were identified following the standard criteria of MR. The primary MR approach employed was the inverse variance weighted (IVW) method, complemented by four additional MR techniques to ensure comprehensive analysis. Extensive sensitivity testing was undertaken to ensure the robustness of the results.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eFindings from the IVW method indicate that an increase by one standard deviation in the level of CD27 ligand elevates the risk of focal epilepsy by 16.6% (OR\u0026thinsp;=\u0026thinsp;1.166, 95% CI: 1.004\u0026ndash;1.354, P\u0026thinsp;=\u0026thinsp;0.045) and generalized epilepsy by 18.6% (OR\u0026thinsp;=\u0026thinsp;1.186, 95% CI: 1.063\u0026ndash;1.323, P\u0026thinsp;=\u0026thinsp;0.0023). Parallel results were observed with the four supplementary MR methods. Sensitivity analyses confirmed these findings to be consistent and not influenced by pleiotropy or other biases.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThis MR analysis reveals a causal link between elevated levels of CD27 ligand and an increased risk of epilepsy, highlighting potential therapeutic targets for intervention. Further research is necessary to confirm these findings and to explore the underlying biological mechanisms.\u003c/p\u003e","manuscriptTitle":"Is CD27 Ligand the Cause of the Increased Incidence of Epilepsy? A mendelian randomization study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-09-06 22:56:14","doi":"10.21203/rs.3.rs-4889861/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ee49577f-755a-4090-a703-127f4d4a5410","owner":[],"postedDate":"September 6th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-29T22:38:41+00:00","versionOfRecord":[],"versionCreatedAt":"2024-09-06 22:56:14","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4889861","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4889861","identity":"rs-4889861","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}